Process for the preparation of 4-amino-beta-phenyl anthraquinone by ring closure



Patented July 14, 1931 UNITED STATES PHILIP H. GROGG-INS, OF WASHINGTON, DISTRICT COLTTMBIA; DETDICATEQUBY AS- SIGNDTENT, TO THE GOVERNIIIENT AND THE PEQPLE Cl THE UEITED STATES OF ATfIERICA PROCESS FOR THE PREPARATION OF d-AMINO-BETAaPHEEYL RING CLOSURE No Drawing.

ANTI-EEAQUINONE, B1

Application filed August a, 1929. Serial no. 384,515.

(GRANTED UNDER THE ACT OF MARCH 3, 1883, AS AMENDED APRIL 30, 1928; 370 O. G. 757) quinone which is a new and valuble intermediate for the preparation of dyestuffs. Other'and further aspects of this invention will be apparent from the disclosures in the specification and appended claims.

I have discovered that l;-amino-paraphenyl-ortho-benZoyl-benzoic acid and itssalts which have been described in my copending application Serial No. 384,510, filed August 8, 1929, under certain conditions lose one molecule of water .and close the ring to form 4 amino-beta-phenyl-anthraquinone.

I This reaction is probably best expressed by the following equation:

The elimination of water from -aminopara phenyl ortho benzoyl-benzoic acid may be brought about by suitable dehydrating agents such as fuming or hydrated sulfuric acid or a mixture of sulfuric acid and boric acid. The fact that this reaction proceeds at all Without sulfonation is quite unexpected, since phenyl-anthraquinone or the ortho substituted products can not be made with sulfuric acid alone as a dehydrating agent, as sulfonation simultaneously occurs and a water soluble product is obtained. Other dehydrating agents such as thionyl chloride or phosphorous pentachloride may also be used.

l-amino-beta-phenyhanthraquinone is a lustrous red product which crystallizes in needles. It gives all the typical reactions of anthraqu'inone derivatives ofthis type, The pure product gives a constant melting point of 222 C. i llithout limiting my invention to any particular procedure the following examples will serve to illustrate my invention in the preferred form:

Elmmplc [.Twenty parts of l-amino para-phenyl-orthobenzoyl-benzoic acid, or the corresponding weight of the amino-sulfate, dissolved in 100 parts of sulfuric acid (monohydrate) and 10 parts of boric acid. The solution is heated to 125 C. and maintained at this temperature for three hours. The -amino-beta-plicnyl-anthraquinone may be separated by fractional crystallization by diluting with water to give a residual acidity of 70 per cent 1 1 530., or the reaction product may be poured into 1000 parts of water. The precipitate is filtered and washed free of mineral. acid with water, and then Washed with dilute alkali. It is then dried at 110 C. The yield is substantially the theoretical. The melting point of the crude product is 218 C. When recrystallized from chlorobenzene it melts at 221.5222 C.

EmampZc H.-Twenty parts of 4aminopara.phenyl-ortho-benzoyl-benzoic acid are treated with 60 parts of 23 per cent fuming sulfuric acid at C. for two hours. The

reaction mass is poured slowly into one liter of iced water under constant agitation. The

precipitated 4 amino beta-phenyl anthra- It is then dried with per cent sulfuric acid as a dehydrating agent.

2. The process of preparing i-amino-betm phenyl-anthraquinone which comprises heating a-amino-para-pheny1-ortho-benZoy1-benzoic acid with amixture of 95 per cent sulfuric acid and boric acid as a dehydrating agent at a temperature of about 125 C.

3. The process of preparing 4-amino-betaphenyl-anthraquinone which comprises heating 4-amino-para-phenyl-ortho-benzoy1-benzoic acid with fuming sulfuric acid as a dehydrating agent at a temperature of about C. for a perod of approximately two hours.

4. The process of preparing 4-amino-betaphenyl-anthraquinone which comprises heating 4-amino-para-pheny1-ortho-benzoyhbenzoic acid with sulfuric acid monohydra-te and boric acid at a temperature of about C. for a period of approximately three hours and diluting the reaction mass with water to precipitate out the 4c-amino-beta-phenyl-anthraquinone.

In testimony whereof, I have hereunto subscribed my name.

PHILIP H. GROGGINS. 

